Anthelmintic Effects of the Essential Oil of Fennel (Foeniculum vulgareMill., Apiaceae) againstSchistosoma mansoni

Therapeutic Potential of Natural Products in the Treatment of Schistosomiasis

It is estimated that 250 million people worldwide are affected by schistosomiasis. Disease transmission is related to the poor sanitation and hygiene habits that affect residents of impoverished regions in tropical and subtropical countries. The main species responsible for causing disease in humans are Schistosoma Mansoni, S. japonicum, and S. haematobium, each with different geographic distributions. Praziquantel is the drug predominantly used to treat this disease, which offers low effectiveness against immature and juvenile parasite forms. In addition, reports of drug resistance prompt the development of novel therapeutic approaches. Natural products represent an important source of new compounds, especially those obtained from plant sources. This review compiles data from several in vitro and in vivo studies evaluating various compounds and essential oils derived from plants with cercaricidal and molluscicidal activities against both juvenile and adult forms of the parasite. Finally, this review provides an important discussion on recent advances in molecular and computational tools deemed fundamental for more rapid and effective screening of new compounds, allowing for the optimization of time and resources.

Salt-Tolerant Plants as Sources of Antiparasitic Agents for Human Use: A Comprehensive Review

Parasitic diseases, especially those caused by protozoans and helminths, such as malaria, trypanosomiasis, leishmaniasis, Chagas disease, schistosomiasis, onchocerciasis, and lymphatic filariasis, are the cause of millions of morbidities and deaths every year, mainly in tropical regions. Nature has always provided valuable antiparasitic agents, and efforts targeting the identification of antiparasitic drugs from plants have mainly focused on glycophytes. However, salt-tolerant plants (halophytes) have lately attracted the interest of the scientific community due to their medicinal assets, which include antiparasitic properties. This review paper gathers the most relevant information on antiparasitic properties of halophyte plants, targeting human uses. It includes an introduction section containing a summary of some of the most pertinent characteristics of halophytes, followed by information regarding the ethnomedicinal uses of several species towards human parasitic diseases. Then, information is provided related to the antiprotozoal and anthelmintic properties of halophytes, determined by in vitro and in vivo methods, and with the bioactive metabolites that may be related to such properties. Finally, a conclusion section is presented, addressing perspectives for the sustainable exploitation of selected species.

Essential Oils as Novel Anthelmintic Drug Candidates

Helminths, with an estimated 1.5 billion annual global infections, are one of the major health challenges worldwide. The current strategy of the World Health Organization to prevent helminth infection includes increasing hygienic awareness, providing better sanitation and preventative anthelmintic drug therapy in vulnerable populations. Nowadays, anthelmintic drugs are used heavily in livestock, both in case of infection and as a preventative measure. However, this has led to the development of resistance against several of the most common drugs, such as levamisole, ivermectin and thiabendazole. As many as 70% of the livestock in developed countries now has helminths that are drug resistant, and multiple resistance is common. Because of this, novel anthelmintics are urgently needed to help combat large-scale production losses. Prior to this review, no comprehensive review of the anthelmintic effects of essential oils and their components existed. Multiple review articles have been published on the uses of a single plant and its extracts that only briefly touch upon their anthelmintic activity. This review aims to provide a detailed overview of essential oils and their components as anthelmintic treatment against a wider variety of helminths.

Antigiardial Activity of Foeniculum vulgare Hexane Extract and Some of Its Constituents

Foeniculum vulgare is used for the treatment of diarrhea in Mexican traditional medicine. Hexane extract showed 94 % inhibition of Giardia duodenalis trophozoites at 300 μg/mL. Therefore, 20 constituents of hexane extract were evaluated to determine their antigiardial activity. Interestingly, six compounds showed good activity toward the parasite. These compounds were (1R,4S) (+)-Camphene (61%), (R)(−)-Carvone (66%), estragole (49%), p-anisaldehyde (67%), 1,3-benzenediol (56%), and trans, trans-2,4-undecadienal (97%). The aldehyde trans, trans-2,4-undecadienal was the most active compound with an IC₅₀ value of 72.11 µg/mL against G. duodenalis trophozoites. This aldehyde was less toxic (IC₅₀ 588.8 µg/mL) than positive control metronidazole (IC₅₀ 83.5 µg/mL) against Vero cells. The above results could support the use of F. vulgare in Mexican traditional medicine.

Antischistosomal Activity of Essential Oils: An Updated Review

This review article covers literature on the antischistosomal activity of essential oils (EOs)( between 2011 and 2021. Criteria for classifying results from in vitro schistosomicidal assays are proposed for the first time. Parameters to evaluate the in vitro antischistosomal potential of EOs other than their ability to cause the death of Schistosoma mansoni adult worms ( e.g ., couple separation, egg laying, and egg development inhibition) are also addressed and discussed.

Anti-Schistosoma mansoni effects of essential oils and their components

Schistosoma mansoni is endemic in 55 countries around the world. S. mansoni is a water-borne parasite of humans belonging to the group of blood flukes. Generally, schistosomiasis is treated with praziquantel, which results in frequent treatment failures and reinfections. Essential oils have diverse biological effects, including antimicrobial, antiprotozoal and antiparasitic. This review aimed at summarizing available in vitro, in vivo and clinical trials showing evidence and mechanisms of actions of essential oils and their derivatives acting against S. mansoni. The findings suggest that a number of essential oils and/or their components act against S. mansoni. Essential oils and/or their derivatives may be one of the potential sources of antischistosomal drugs.

Ovicidal and larvicidal activity of extracts from medicinal-plants against Haemonchus contortus

The use of medicinal plants (MP) containing bioactive compounds is an alternative strategy to control of parasitic nematode of small ruminants Haemonchus contortus at various stages of their life cycle. The aims of this study were to determine the in vitro anthelmintic activity of both aqueous and methanolic extracts from 13 medicinal plants typical for Central Europe, and to determine quantity of selected plant secondary metabolites (PSMs) in the methanolic extracts. In vitro egg hatch test and larval development tests were conducted to determine the possible anthelmintic effects of methanolic and aqueous extracts of the roots of Althaea officinalis L., Petasites hybridus L. and Inula helenium L.; flowers of Malva sylvestris L. and Chamomilla recutita L.; leaves of Plantago lanceolata L. and Rosmarinus officinalis L.; seeds of Foeniculum vulgare Mill. and stems of Solidago virgaurea L., Fumaria officinalis L., Hyssopus officinalis L., Melisa officinalis L. and Artemisia absinthium L. on eggs and larvae of H. contortus. Ultra-performance liquid chromatography and tandem mass spectroscopy was used for quantifying six PSMs: gallic acid (GA), rutin (RU), diosmin (DI), hesperidin (HE), quercetin (QU) and kaempferol (KA). RU content of the most effective methanolic extracts was in the order: M. sylvestris (9.33 mg/g DM) > A. absinthium (6.10 mg/g DM) > C. recutita (0.42 mg/g DM). The highest concentration of QU (44.8 mg/g DM) and KA (6.59 mg/g DM) were detected in stems of F. officinalis comparing to the other evaluated plants. The most significant (p < 0.05) anthelmintic effects exhibited methanolic extracts of A. absinthium in both in vitro tests (i.e., egg hatch test and larval development test). Additionally, only two methanolic extracts of C. recutita and M. sylvestris were comparable to activity of A. absinthium using the larval development test. Wider spectrum of aqueous extracts exhibited stronger ovicidal activity in comparison to methanolic extracts. The similar trend was observed in evaluating of larvicidal activity of aqueous and methanolic plant extracts.

Large Scale Geographical Mapping of Essential Oil Volatiles in Heracleum (Apiaceae): Identification of Novel Compounds and Unraveling Cryptic Variation

Conspecific populations of plants in their native range are expected to show considerable variation due to long-term ecological and evolutionary factors. We investigated the levels of secondary metabolites in Heracleum including H. persicum a valuable medicinal plant to depict the magnitude of cryptic variation and the potential significance of novel chemical traits. The essential oil volatiles from fruits of 34 populations from different species of Heracleum in Iranian distribution range and a native of H. sphondylium and an invasive population of H. persicum from Norway were analyzed with GC/MS. Out of 48 compounds identified, a contrasting pattern in the level of two major compounds, octyl acetate and hexyl butyrate was found among all studied species. Interestingly, a significant geographic pattern was observed; the hexyl butyrate/octyl acetate ratio was high (range 1.8 - 3.2) in the northwestern Iranian populations of H. persicum compared to that in northern and central populations (range 0.3 - 0.9). Four populations from Zagros mountains also exhibited a unique composition. Anethole was found in two populations of H. persicum from central Zagros, which has not been previously reported for essential oil of fruits of Heracleum so far. The results suggest high efficiency of large scale sampling from distribution range of species in identifying novel compounds. The unique pattern of geographic structuring also provides novel information to unravel cryptic variation in Heracleum.

The Confrontation between Ethnopharmacology and Pharmacological Tests of Medicinal Plants Associated with Mental and Neurological Disorders

For neurological disorders, pharmacological tests have shown promising results in the reduction of side effects when using plants with known therapeutic effects in the treatment of some types of dementia. Therefore, the goals of this study are to gather data about the major medicinal plants used in the nervous system as described in ethnopharmacological surveys from South America and Brazil and to compare this data with the results from pharmacological tests on the active principles of those same plants found in the scientific literature. After collecting the data about each plant, their respective popular indication was compared with the results found through pharmacological tests. The discrepancy rate between the effects observed by ethnopharmacological and pharmacological methods in this study is greater than 50%. In conclusion, despite the importance of ethnopharmacological data, it is important to make comparisons with pharmacological tests for the same plants, since the pharmacological studies, although few, have shown a high rate of discrepancy in the results.

Chemical Composition and Antibacterial Activity of the Essential Oil of Vitex agnus-castus L. (Lamiaceae)

Abnormal multiplication of oral bacteria causes dental caries and dental plaque. These diseases continue to be major public health concerns worldwide, mainly in developing countries. In this study, the chemical composition and antimicrobial activity of the essential oil of Vitex agnus-castus leaves (VAC‒EO) collected in the North of Brazil against a representative panel of cariogenic bacteria were investigated. The antimicrobial activity of VAC-EO was evaluated in terms of its minimum inhibitory concentration (MIC) values by using the broth microdilution method in 96-well microplates. The chemical constituents of VAC-EO were identified by gas chromatography (GC‒FID) and gas chromatography‒mass spectrometry (GC‒MS). VAC‒EO displayed some activity against all the investigated oral pathogens; MIC values ranged from 15.6 to 200 μg/mL. VAC-EO had promising activity against Streptococcus mutans (MIC= 15.6 μg/mL), Lactobacillus casei (MIC= 15.6 μg/mL), and Streptococcus mitis (MIC= 31.2 μg/mL). The compounds 1,8-cineole (23.8%), (E)-β-farnesene (14.6%), (E)-caryophyllene (12.5%), sabinene (11.4%), and α-terpinyl acetate (7.7%) were the major chemical constituents of VAC‒EO. VAC-EO displays antimicrobial activity against cariogenic bacteria. The efficacy of VAC-EO against S. mutans is noteworthy and should be further investigated.

Phosphate and Phosphonate-Based Ionic Liquids as New Additives in Foeniculum vulgare Essential Oil Extraction

The effect of the addition of four different halide-free ionic liquids (ILs) during the maceration step on Foeniculum vulgare essential oil (EO) extraction by hydrodistillation was investigated. The EO yields and their chemical composition were also evaluated, as well as the possibility of reusing the IL aqueous solutions. Although all the investigated ILs were able to increase EO yields, 1,3-dimethylimidazolium dimethylphosphate (IL1) showed the best performance. In particular, the 1 : 1 IL1–water mixture increased the EO yield by ~40 %, even after three reuses, maintaining practically the same volatile profile.

Chemical Composition, Antibacterial, Schistosomicidal, and Cytotoxic Activities of the Essential Oil of Dysphania ambrosioides (L.) Mosyakin & Clemants (Chenopodiaceae)

We have investigated the chemical composition and the antibacterial activity of the essential oil of Dysphania ambrosioides (L.) Mosyakin & Clemants (Chenopodiaceae) (DA-EO) against a representative panel of cariogenic bacteria. We have also assessed the in vitro schistosomicidal effects of DA-EO on Schistosoma mansoni and its cytotoxicity to GM07492-A cells in vitro. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) revealed that the monoterpenes cis-piperitone oxide (35.2%), p-cymene (14.5%), isoascaridole (14.1%), and α-terpinene (11.6%) were identified by as the major constituents of DA-EO. DA-EO displayed weak activity against Streptococcus sobrinus and Enterococcus faecalis (minimum inhibitory concentration (MIC) = 1000 μg/ml). On the other hand, DA-EO at 25 and 12.5 μg/ml presented remarkable schistosomicidal action in vitro and killed 100% of adult worm pairs within 24 and 72 h, respectively. The LC₅₀ values of DA-EO were 6.50 ± 0.38, 3.66 ± 1.06, and 3.65 ± 0.76 μg/ml at 24, 48, and 72 h, respectively. However, DA-EO at concentrations higher than 312.5 μg/ml significantly reduced the viability of GM07492-A cells (IC₅₀  = 207.1 ± 4.4 μg/ml). The selectivity index showed that DA-EO was 31.8 times more toxic to the adult S. mansoni worms than GM07492-A cells. Taken together, these results demonstrate the promising schistosomicidal potential of the essential oil of Dysphania ambrosioides.

Biological Activities of Essential Oils: From Plant Chemoecology to Traditional Healing Systems

Essential oils are complex mixtures of hydrocarbons and their oxygenated derivatives arising from two different isoprenoid pathways. Essential oils are produced by glandular trichomes and other secretory structures, specialized secretory tissues mainly diffused onto the surface of plant organs, particularly flowers and leaves, thus exerting a pivotal ecological role in plant. In addition, essential oils have been used, since ancient times, in many different traditional healing systems all over the world, because of their biological activities. Many preclinical studies have documented antimicrobial, antioxidant, anti-inflammatory and anticancer activities of essential oils in a number of cell and animal models, also elucidating their mechanism of action and pharmacological targets, though the paucity of in human studies limits the potential of essential oils as effective and safe phytotherapeutic agents. More well-designed clinical trials are needed in order to ascertain the real efficacy and safety of these plant products.

Evaluation of titanium dioxide nanocrystal-induced genotoxicity by the cytokinesis-block micronucleus assay and the Drosophila wing spot test

Titanium dioxide nanocrystals (TiO2 NCs) crystalline structures include anatase, rutile and brookite. This study evaluated the genotoxic effects of 3.4 and 6.2 nm anatase TiO2 NCs and 78.0 nm predominantly rutile TiO2 NCs through an in vitro micronucleus (MN) assay using V79 cells and an in vivo somatic mutation and recombination test in Drosophila wings. The MN assay was performed with nontoxic concentrations of TiO2 NCs. Only anatase (3.4 nm) at the highest concentration (120 μM) induced genotoxicity in V79 cells. In the in vivo test, Drosophila melanogaster larvae obtained from standard (ST) or high bioactivation (HB) crosses were treated with TiO2 NCs. In the ST cross, no mutagenic effects were observed. However, in the HB cross, TiO2 NCs (3.4 nm) were mutagenic at 1.5625 and 3.125 mM, while 78.0 nm NCs increased mutant spots at all concentrations tested except 3.125 mM. Only the smallest anatase TiO2 NCs induced mutagenic effects in vitro and in vivo. For rutile TiO2 NCs, no clastogenic/aneugenic effects were observed in the MN assay. However, they were mutagenic in Drosophila. Therefore, both anatase and rutile TiO2 NCs induced mutagenicity. Further research is necessary to clarify the TiO2 NCs genotoxic/mutagenic action mechanisms.